Effect of noise and detection error is one of three important factors affecting the performances of an adaptive optics (AO) system. In an AO system, noise and detection error can produce errors in the tilt detection of a Hartmann Shack (H S) wavefront sensor and have further effects on the performance of the AO System. A theoretical model of numerically simulating the effects of noise and detection error is presented and a computer program has been compiled, which is combined with our existing program of numerical simulation of the laser propagation in turbulent media and an AO system. The effects of detection error, readout noise and photon noise on a practical AO system have been namerically simulated. The results are quite useful for the design of a practical AO system.

A novel Y branch waveguide structure is presented, in which a transitional guide is embedded between an incident channel and an output branch. The transitional guide is used to improve the mode field matching between both the waves supported by the incident and output waveguides. A numerical simulation shows that this geometry can minimize the branching loss to about 0.041 dB at 1.31 μm and 0.052 dB at 1.55 μm wavelength respectively. The samples of this type SiO 2 branch waveguide are fabricated by the chemical vapor deposition technology. The measurement on the samples gives the good results of about 0.08 dB and 0.09 dB branching loss at 1.31 μm and 1.55 μm wavelengths respectively.

Comparsions of single mode waveguide conditions for single mode silicon on insulator (SOI) and GeSi/Si rib waveguides obtained by the effective index method (EIM) and proposed by Soref et al. with the experimental result are carried out. It is found that single mode waveguide condition obtained by effective index method is in good agreement with Rickman′s experimental result. Conditions for multimode rib waveguides loading the first and the second order mode are also obtained by effective index method.

Analytical solutions of a double cladding (W type) chiral optical fiber which both core and claddings are chiral media have been presented. The solutions of guided modes and modal characteristic equation are derived. The effects of chirality on dispersion curves and cut off freqencies of guided modes are studied by numerical method.The single mode operation can be supported by using chiral core material in the double cladding optical fiber or using chiral cladding material in the single cladding optical fiber.

Cladding mode coupling will lead loss on the shoft wavelength side of Bragg wavelength and thus limits the grating’s wide use. A novel photosensitive fiber design is proposed that have both the depressed cladding and the photosensitive inner cladding in the same fiber. It can suppress cladding mode coupling in some extent. B/Ge co coped fiber grating with depressed cladding also doped with boron and gemania was fabricated. The transmission spectrum of written grating in it verified its larger photosensitivity and suppression of cladding mode coupling.

By using holographic tow step storage method, a group of brain magnetic resonance imaging (MRI) slices were recorded in a depth multiplexed hologram. Reconstructed under incandescent lamp, a clear three dimensional perspective image of brain can be viewed. The holograms can aid doctors to diagnose and locate the disease accurately and quickly.

Optical design of a novel spherical grating monochromator is described, which is used in testing the soft X ray spectra of a low debris laser produced plasma (LPP). By employing a variable deviation angle at the grating, it is possible to exactly focus the entrance slit on the exit slit in the wavelength range of 3 nm～20 nm. The effect of the key parameters is analyzed, and the optimum design is implemented. A resolution of λ/ Δ λ≥2000 at 13 nm has been achieved (the entrance slit is 50 μm).

A new laser diode interferometer for micro vibration measurement is proposed. The interferometer can measure micro vibrations of an object in real time. The interference signal is analyzed with signal processing circuits and the amplitude and frequency of vibrations are obtained. The theory analysis is described. The experimental results verify the usefulness of the interferometer.

The phase indeterminacy of single frequency fringe pattern and bi frequency fringe pattern in phase analysis method has been theoretically analyzed. The phase data can be determined when the ratio of two frequencies is an irrational number in spatial bi frequency fringe pattern. A simple and robust phase unwrapping by a lookup table method for this bi frequency fringe pattern is proposed. Experimental results are presented that demonstrate the validity of the method.

A novel all optical scheme for clock recovery is demonstrated by non uniform optical time division multiplexing (OTDM) optical signal injection into model locked optical fiber laser. In experiment, 2.5 GHz subharmonic frequency clock signal is recovered from 4×2.5 GHz OTDM signal. The technique can be used in clock recovery in high speed OTDM communication.

It is analyzed that the physical mechanism of decreasing the amplitude fluctuation of output pulse train and eliminating some noise as well as compressing and shaping the pulse train by using a nonlinear optical loop mirror (NOLM). Experimentally the NOLM is placed in an actively harmonic mode locked erbium doped fiber ring laser to form an actively and passively mode locked Er doped fiber laser (APHML EDFL). By means of function of saturable absorber of NOLM, the noise of the fourth rational harmonic mode locked (RHML) pulse train is successfully suppressed and the fourth harmonic mode locked of very stable amplitude with repetition rate of 5.1 GHz is obtained with modulation frequency of 1 GHz.

The technology of the periodic poling LiNbO 3 (PPLN) by applying external field was experimentally studied. A periodic Al electrode was formed on one side of Z cut LiNbO 3 and uniform electrode on the other side by photolithographic in 0.5 mm thick samples. A series of high voltage pulses was applied between the electrodes at room temperature. The voltage application was performed under various conditions including magnitude, duration of voltage pulse and the peak current. The third quasi phase matched periodic poling LiNbO 3 (PPLN) with periods of 9.5 μm was fabricated.

The grey scale display in multidomain surface stabilized ferroelectric liquid crystal (SSFLC) structure is observed and the transmittance votage dependence in SSFLC pixel is measured. The influences of the RC constant of conductive glass and the duration of the selective pulse on the response waveforms are discussed. By analyzing the various waveforms, the mechanism underlying this kind of grey scale is presented.

A method to calculate the emission cross section of rare earth ions was introduced based on the combination of the McCumber theory with Judd Oflet theory. The method is very simple and only needs to measure the absorption spectra. The emission cross sections of Tm 3+ , Yb 3+ and Er 3+ ions from the first excited state to the ground state were calculated in this way. The results indicated that the method is practical.

Cr 3+ ion doped YAG (Cr 3+ ∶YAG) layers grown by LPE is a newly developed single crystalline cathodoluminescent phosphor with a broad emission in red band. The maximum intensity of Cr 3+ emission in YAG is at λ max ≈689 nm, 709 nm with a color point of x=0 6551, y=0 2949, which is of the same chromaticity with a red emission of λ=638 nm. The abundant red components of Cr 3+ emission in the vicinity of λ≈700 nm give a deep impression, this made Cr 3+ ∶YAG of great value in the development of high resolution α Si∶H liquid crystal light valve projection display.

A new subphthalocyanine (bromoboron trinitro subphthalocyanine) thin film was prepared by vacuum deposition on a single crystal silicon substrate. The ellipsometric spectra of this film have been investigated on an improved rotating analyser polarizer (RAP) type of scanning ellipsometer. The optical and dielectric constants, absorption coefficient and trapping levels of this film in the 400 nm～700 nm wavelength region were given. The spectra were explained and discussed as well.

The phase change films were deposited on K 9 glass substrate by RF magnetron sputtering technique with an Ag In Sb Te alloy target. The as deposited films were annealed at 300 ℃. The influences of background pressure, sputtering pressure and sputtering power on the optical properties of the phase change films are studied. It was found that the optical properties of the phase change films were synthetically determined by sputtering parameters and lower background pressure, while the proper sputtering pressure and sputtering power were very important for the AgInSbTe phase change films.

Soft X ray laser radiation ranged from 40 nm to 110 nm is obtained by the 7th to the 19th order harmonic generation in krypton with femtosecond Ti∶sapphire laser operating at 780 nm, and the same phenomena especially the spectral shift is observed after the central wavelength of Ti∶sapphire laser is tuned to 795 nm. So the high order harmonic generation is confirmed. The spectrum change pumped by linear polarization laser and the spectrum intensity change with gas pressure are also observed.

The refractive index of many materials depends upon the intensity of the light propagating through it. The optical activity will be varied due to the changed refractive index. The practical formulation of Δ n is given. The characteristic about the nonlinear optical activity vs. elliptically character parameter is analyzed. The nonlinear rotation angle of chiral medium (P thienylenevinylene) under normal optical field is calculated.

The nonlinear optical properties of cluster WOS 3Cu 3I(2 MePy) 3 by using the Z scan method were studied. The experimental results were simulated based on the steady state solution of rate equations, and the third order nonlinear optical parameters of the cluster were obtained. The theoretical curves are in good agreement with experimental results. The relationship between the sign of the nonlinear refraction index and the ratio of the refrangibilities K r has also been studied. It is demonstrated that when K r>1 the nonlinearity is positive, while K r<1 negative. Numerical results are in consistent with the theory.

With the developing of space science and technology, the ability of remote sensing and reconnaissance are improved. So higher resolution capability of image system is needed. The resolution of some image system is high in static condition. But image motion or mechanical vibration limits the resolution. The degradation of image quality as a result of motion in the image plane can be evaluated by optical transfer function of motion. A new method to calculated optical transfer function——statistic moments method is discussed. Analytical and numerical methods to calculate optical transfer function of motion are studied when the image moves in the image plane two dimensionally. This method can be used to calculate the degradation of image quality as a result of any kind of image motion in the image plane, and easily used in the case of one dimensional motion.

The performance of fiber Bragg grating glued on a cantilever beam used for current sensing is analyzed and demonstrated. The isosceles triangle shaped beam makes the grating chirp free and, hence, reduces the reading error. The measured sensing sensitivity is 4.00×10 -2 nm/A which is close to the predicted value of 4.15×10 -2 nm/A.

Causes affecting behaviors of the optical add/drop multiplexer (OADM) based on Mach Zehnder interferometer and fiber Bragg gratings have been discussed. Based on theoretical analysis and simulation, a method of analyzing and adjusting the parameter of the OADM by monitoring the back reflected spectrum at the input port and by local heating has been proposed. It can also be used to simulate the process of trimming by UV exposure. Experimental results have proved the feasibility of this method.

A new superresolution element is proposed to increase the resolution of an optical system by improving part of the spatial frequency. i.e., to shift the lower spatial frequency light to high spatial frequency band. It makes the central maximum in the Airy pattern narrower and increases the depth of focus. Calculation results have shown that this kind of apodizer is superior to the phase-shifting apodizer.

The Sr Faraday dispersion optical filter at 460.7 nm in Fraunhofer dip was analyzed. The filtering properties of the filter at line wing and central operation were analysed respectively. The influence of magnetic field, temperature and cell length on the filter operaton was discussed. Under the best operation conditions the transmission at line centre is up to 95%, and bandwidth is about 1.47 GHz.

A novel organic electroluminescent device with EuGd complex (Eu 0.1 Gd 0.9 )(TTA) 3(TPPO) 2 as an emitter was developed. The characteristics of this device were described and both fluorescence and phosphorescence were observed. This phenomenon is discussed in terms of yields of phosphorescence from the triplet excited state of the Gd and Eu chelates because of the paramagnetic Gd 3+ ion strong perturbance to the spin orbit levels of the complex. Both the photoluminescent and electroluminescent efficiencies at different temperature from 77 K to 300 K were measured by integrating sphere technique. The results imply that the phosphorescent emission from the triplets excited state might be a new way to increase the theoretical efficiency limit in electroluminescent devices.

Two improvements have been made to Rouard′s method for the analysis of fiber and waveguide gratings. The element of reflection is chosen to be a section of half period instead of a period, and the real reflectivity of each interface is used instead of an approximate value obtained by coupled mode theory. The improved Rouard′s method becomes a complete Rouard′s method with higher accuracy. It is simple and independent on coupled mode theory for no calculation of the coupling coefficient required. Numerical examples of uniform and nonuniform gratings are given.

The interaction between femtosecond optical pulses is studied by using numerical simulation. The results show that the interaction is different from that between picosecond optical pulses. Under the circumstance of nearer separation between solitons, the later is periodic repulsion and attraction, but the interaction of the former is more serious. At the initial moment, the interaction of femetosecone optical pulses is the same as that of picosecond optical pulse, but after the soliton pair become one pulse, they keep the state of repulsion and the separation between solitons increases along the distance. These can cause larger error code rate. The results also show that unequal amplitude method can reduce the interaction between femtosecond soliton in a certain degree.

With the help of the turbulent cell, an experiment is carried out to simulate light propagation in atmospheric convective boundary layer. At the same time, fluctuation of arrival angle and fluctuation of temperature are sampled. The results show, in the upper mixed layer, the logarithmic temperature spectrum becomes more steeper than “-5/3” in the frequency range f>0.1 Hz (It accords with the fact of atmospheric boundary layer), and the logarithmic arrival angle spectrum becomes more steeper than “-8/3”, C 2 n obtained by means of temperature fluctuation is lower than by means of arrival angle. When the inversion disappears, the temperature spectrum follows the inertial sub range “-5/3 law”, and the power of arrival angle spectrum is “-8/3”, C 2 n calculated by two methods is same.

The Collins formula in spatial frequency domain is generalized into axially nonsymmetrical optical system in terms of tensor analysis method. Based on this formula, the tensor ABCD law in spatial frequency domain is derived. The Collins formula and tensor ABCD law in spatial frequency domain provide the relation between the input spatial Fourier spectrum and the output spectrum directly. They have advantages in treating the problems concerned with spatial Fourier spectrum, such as spatial frequency filtering, optical transfer function of imaging systems and the propagation of general astigmatic Gaussian beam in free space, and so on.

The frequency tunable amplitude squeezed light of the continuous tunable range over 1 GHz around the D 2 line of Cesium (Cs) at 852.356 nm and the squeezing degree about 0.8 dB was experimentally generated with an injection locked laser diode. The amplitude squeezed light was applied in the frequency modulation (FM) spectroscopy measurement of Cs saturated vapor, the signal to noise ratio (SNR) of which was improved about 0.7 dB relative to the shot noise limit (SNL).

The phase properties of two mode SU (1,1) coherent field interacting with two atoms are investingated by means of the phase formalism given by Pegg and Barnett. It is found that single mode phase and the difference of the two mode phase are all randomly distributed. The expressions of variance of the phase sum are presented. It is verified that the atomic coherent trapping will take place in a appropriate initial state of the system.